A federal appeals court removed a serious legal challenge to the Bush administration's warrantless wiretapping program Friday, overruling the only judge who held that a controversial surveillance initiative by the National Security Agency was unconstitutional.

Two members of a three-judge panel of the U.S. Court of Appeals in Cincinnati ordered the dismissal of a major lawsuit that challenged the wiretapping, which President Bush secretly authorized to eavesdrop on communications involving potential terrorists shortly after the Sept. 11 attacks.

The court did not rule on the spying program's legality. Instead, the decision found that the American Civil Liberties Union, academics, lawyers and journalists who brought the case did not have standing to sue because they could not demonstrate that they had been direct targets of the clandestine surveillance.

The decision vacates a ruling in the case in August by a U.S. District Court judge in Detroit who found that the administration's program to monitor private communications violated the Bill of Rights and a 1970s federal law.

The eavesdropping program -- first revealed by news accounts in late 2005 and the subject of intense political wrangling since then -- is one aspect of a broad assertion of presidential power Bush has invoked in the past six years to justify policies intended to deter terrorism domestically and abroad.

As first devised, the Terrorist Surveillance Program allowed the National Security Agency to intercept telephone calls and e-mail between the United States and overseas, in which at least one party was suspected to be affiliated with al Qaeda or related groups, without the court approval typically required for government wiretaps, according to administration officials.

ACLU legal director Steven Shapiro said the organization was examining its legal options, including the possibility of an appeal to the Supreme Court.

Friday's ruling leaves two other challenges to the surveillance program alive and awaiting an Aug. 15 hearing by the U.S. Court of Appeals in San Francisco.

One suit is a class action by customers of AT&T, who say the company illegally turned over their telephone and e-mail records to the National Security Agency to be screened for possible terrorist contacts.

Chief U.S. District Judge Vaughn Walker refused to dismiss the suit last year, rejecting the government's claim that allowing the case to proceed would expose military secrets and endanger national security. Walker said the customers had legal standing to sue -- the critical issue in Friday's ruling -- because the company's alleged furnishing of their records to the government affected their rights.

The second suit before the appeals court was filed in Oregon by a now-defunct Muslim charity, the al-Haramain Islamic Foundation, which -- unlike any other plaintiff in the surveillance suits -- says it has documents showing its communications were monitored.